<template>
    <div class="app-container">
        <el-input v-model="filename" placeholder="Please enter the file name (default excel-list)" style="width:350px;" prefix-icon="el-icon-document" />
        <el-button :loading="downloadLoading" style="margin-bottom:20px" type="primary" icon="el-icon-document" @click="handleDownload">
            Export Selected Items
        </el-button>
        <a href="https://panjiachen.github.io/vue-element-admin-site/feature/component/excel.html" target="_blank" style="margin-left:15px;">
            <el-tag type="info">Documentation</el-tag>
        </a>
        <el-table
            ref="multipleTable"
            v-loading="listLoading"
            :data="list"
            element-loading-text="拼命加载中"
            border
            fit
            highlight-current-row
            @selection-change="handleSelectionChange"
        >
            <el-table-column type="selection" align="center" />
            <el-table-column align="center" label="Id" width="95">
                <template slot-scope="scope">
                    {{ scope.$index }}
                </template>
            </el-table-column>
            <el-table-column label="Title">
                <template slot-scope="scope">
                    {{ scope.row.title }}
                </template>
            </el-table-column>
            <el-table-column label="Author" width="110" align="center">
                <template slot-scope="scope">
                    <el-tag>{{ scope.row.author }}</el-tag>
                </template>
            </el-table-column>
            <el-table-column label="Readings" width="115" align="center">
                <template slot-scope="scope">
                    {{ scope.row.pageviews }}
                </template>
            </el-table-column>
            <el-table-column align="center" label="PDate" width="220">
                <template slot-scope="scope">
                    <i class="el-icon-time" />
                    <span>{{ scope.row.display_time }}</span>
                </template>
            </el-table-column>
        </el-table>
    </div>
</template>

<script>
import { fetchList } from "@/api/article";

export default {
    name: "SelectExcel",
    data() {
        return {
            list: null,
            listLoading: true,
            multipleSelection: [],
            downloadLoading: false,
            filename: ""
        };
    },
    created() {
        this.fetchData();
    },
    methods: {
        fetchData() {
            this.listLoading = true;
            fetchList(this.listQuery).then(response => {
                this.list = response.data.items;
                this.listLoading = false;
            });
        },
        handleSelectionChange(val) {
            this.multipleSelection = val;
        },
        handleDownload() {
            if (this.multipleSelection.length) {
                this.downloadLoading = true;
                import("@/vendor/Export2Excel").then(excel => {
                    const tHeader = ["Id", "Title", "Author", "Readings", "Date"];
                    const filterVal = ["id", "title", "author", "pageviews", "display_time"];
                    const list = this.multipleSelection;
                    const data = this.formatJson(filterVal, list);
                    excel.export_json_to_excel({
                        header: tHeader,
                        data,
                        filename: this.filename
                    });
                    this.$refs.multipleTable.clearSelection();
                    this.downloadLoading = false;
                });
            } else {
                this.$message({
                    message: "Please select at least one item",
                    type: "warning"
                });
            }
        },
        formatJson(filterVal, jsonData) {
            return jsonData.map(v => filterVal.map(j => v[j]));
        }
    }
};
</script>
